1. Field of Invention
The present invention relates to a very sensitive, practical, useful, widely available diagnostic kit for fungal skin infections.
2. Backgroundxe2x80x94Description of Art
Fungal skin infection is a common medical problem worldwide. In the United States, one of every five persons gets a fungal infection at some time. Athlete""s foot (tinea pedis) is the most common fungal skin infection. It affects approximately 70 percent of adult population. Many people, especially teenagers and young men will acquire it at least once in a lifetime. Factors predisposing to athlete""s foot include heavy sweating, not drying feet after bathing, warm and moist climate, heavy-duty athletic activities and tight shoes and socks, especially made of synthetic materials. Other fungal skin diseases may involve the groin area (jock itch), underarms, legs, face and chest and back (tinea versicolor). Fungal infections of the skin may manifest as skin discoloration (pale, dark, red patches), itching, burning, pain and discomfort. The skin can become brittle and scaling can occur. Occasionally the skin can develop fissures, blisters and ulcers followed by scarring. Infections, if left untreated, may lead to cellulitis, sever pain and discomfort and even to systemic dissemination of the disease. Especially serious problems may be encountered in diabetic and immunocompromised patients. Offensive clinical presentation of the disease can also lead to social stigma with negative effect on self-esteem and social interaction.
A firm, definite diagnosis of fungal skin diseases is crucial before prescribing antifungal agents. All medications carry a potential risk for toxic reactions and drug interactions and many medications are costly. The list of diagnostic tools for fungal skin diseases in a clinical setting includes potassium hydroxide (KOH) preparation, fungal cultures and surgical pathology diagnostic tests. KOH preparation appears to serve as a most commonly utilized diagnostic test followed by cultures. Both KOH and surgical pathology diagnostic tests involve scraping of the superficial layer of skin with scalpel or glass slide edge. This procedure is considered invasive and has to be performed in doctor""s office by a trained medical practitioner.
In KOH preparation, the specimen is placed on a microscopic slide, softened by 20% KOH, and heated under a heat source. The specimen is then evaluated microscopically for the presence of fungal elements (yeasts and hyphae). In surgical pathology diagnostic test the skin scrapings are stained with periodic acid-Schiff reaction (PAS) and also examined under microscope. In fungal cultures, the specimen is usually placed on dermatophyte test and Sabouraud dextrose agar media. Cultures are allowed four weeks to grow. At the end of this period, fungal samples are removed from the media, stained with lactophenol blue, and examined microscopically for the identification of specific genus and species. Unfortunately cultures can take as long as a month to grow and approximately 30-40% of cultures may be negative.
Interestingly, in fungal skin infections, the usual location of the causative fungus is in the outermost layer of the skin. This layer is called cornified layer or stratum cornum. This part of the skin is dead and easily detachable. The cell from the cornified layer are constantly slough in a natural process. I made an observation that these cells can even be easily lifted with a self adhesive tape like Scotch tape(copyright). This fact led me to create an idea of highly sensitive, useful, non-invasive, widely available diagnostic kit for fungal skin infections.
The objectives of the proposed invention are to provide the general public, cosmetologists and health care providers (podiatrists, dermatologists, family practitioners, physical therapists, internists, orthopedists, etc) with a simple, highly sensitive, useful, practical, non-invasive, safe, informative, widely available, and inexpensive diagnostic kit for fungal skin infection.
The basis of the invention is the usual location of pathogenic fungi within dead, easily detachable outermost layer of the skin. The invention is also based on superior sensitivity and usefulness of histochemical PAS stain in tissue preparations. The Diagnostic Test Kit for fungal skin diseases can include colorful, attractive packaging (FIG. 1). The kit can also include a translucent, plastic diagnostic slide with retractable, self adhesive, centrally translucent tape (FIG. 2). The kit will also contain a plastic, zip-lock type, biohazard specimen bag (FIG. 3) and a return, prepaid envelope (FIG. 4). The kit can include medical information about fungal skin infections and use an instruction booklet. Each kit can have a specific computerized identification number. The user or customer, such as a person with suspicious looking skin changes (e.g. discolored, thickened, fissured, cracked, peeling, itching skin), will preferably be able to purchase the kit in the drug stores, grocery stores, health oriented stores, beauty salons, health salons, doctors offices, etc. The customer can be able to become familiar with medical aspects of fungal skin infections from the medical information booklet. The instructions booklet can specify how to obtain diagnostic sample of cornified layer of the skin using provided plastic slide with attached adhesive tape. (FIG. 2). The suspicious area of the skin can be touched with adhesive part of the tape. The customer can be instructed to reattached the tape to the plastic slide, place the slide in the specimen bag and mail the sample to the skin fungus diagnostic lab using provided prepaid envelope. In the laboratory the slide and the tape can be partially detached and stained with PAS stain. A pathologist can read the slide and make the diagnosis for presence or absence of fungal skin infection. A written result report can be faxed/mailed to the clinician in charge of the patient/customer or send to the computerized, telephone or Internet report system. The customer can then have the opportunity to obtain the diagnosis and medical recommendation message over the phone (or internet) using his identification number. The specimen processing system offers opportunity for potential automatization. Trained technicians could also prescreen the slides.